The date, his 75th birthday, also marks the Carnegie Hall premiere of his Ninth Symphony.

The completion of nine symphonies is a peculiar sort of landmark in the classical-music world. Despite some outliers (Dmitri Shostakovich wrote 15, for instance), a number of major composers simply stopped producing symphonies after No. 9, among them Beethoven, Schubert, Bruckner, Dvorak, Mahler and Vaughan Williams.

Glass, who will perform Thursday at Miami Beach’s New World Center for the Rhythm Foundation, admits that eery reality gave him pause.

“There was part of my awareness that was saying, ‘My God, it’s the Ninth Symphony. What the hell am I going to do?’” he says from his home in New York. “There was kind of a sub-cortical chant in my head all the way through.

“But when I got done with it, I went on tour. And when I came back a couple weeks later, I looked at it, and I said: ‘Oh. It’s OK. It’s working out OK.’ And then I began to do a few rewrites. I was a little freaked out when I was doing it, but once I got the first draft done, I was fine.”

Thus speaks the practical composer unbruised by critical brickbats, undaunted by performance logistics, unswayed by superstition. Such a stance has suited Glass well throughout what has been probably the biggest American classical-composing career of the past four decades.

Since the early 1970s, and particularly with the appearance of his opera Einstein on the Beach in 1976, Glass has espoused a distinctive minimalism that has bewitched some listeners — and infuriated others — with its repetitive structures and slow, subtle harmonic shifts. He is surely the only American contemporary classical composer with whose music general audiences are broadly familiar, if only for his movie scores, which include those for The Truman Show, The Hours (a Golden Globe winner), Kundun and The Illusionist, as well as for the Godfrey Reggio trilogy that begins with Koyaanisqatsi.

A native of Baltimore who studied at the University of Chicago and Juilliard, Glass worked with the great French pedagogue Nadia Boulanger and sitar master Ravi Shankar early in his career and famously drove a cab and did plumbing odd jobs in New York while writing for his Philip Glass Ensemble. All the while, he was charting a new path for contemporary music with other minimalists such as Steve Reich and Terry Riley, though Glass’ music has eclipsed that of the others.

This wave of composers broke free of the atonal paradigm, derived from the work of Arnold Schoenberg, which was then considered de rigueur for new music — and, to some extent,. still is.

“One of his impacts has been that his success gave other composers permission to work in more tonal ways,” says John Warthen Struble, a Wolfeboro, N.H.-based composer, teacher and writer whose The History of American Classical Music features a foreword by Glass. “Certainly he wasn’t the only one working in tonality. George Rochberg [perhaps best known for his Concord string quarters], for instance, left serialism for what he considered classical tonalism, and Leonard Bernstein had always worked in tonality.

“But as an avant-garde composer, part of the New York underground south of 14{+t}{+h} Street,” Struble says, Glass “gave the avant-garde the ability to work in different ways than they had before.”

For his Miami Beach concert, Glass says he likely will play six etudes, along with other pieces.

“I wrote the etudes for myself, to improve my piano playing. I picked specific pianistic issues that I wanted to address, and I wrote pieces of music which I knew would address the issues, and you know what? It worked. I ended up being a better pianist because I wrote the etudes.”His performs them as concert pieces, “because they are also in the world of abstract or pure music, and they seem to function perfectly well in that world.”

“We really consider him a seminal figure in the opening of American ears to another way of listening, to another way of hearing music,” says James Quinlan, Rhythm Foundation chairman. “Philip’s sense of time and harmonic development are more attuned to international traditions than many Western traditions.”

The foundation last hosted Glass a few years back for a show at the Lincoln Theatre in which the composer appeared with Foday Musa Suso, an eminent Gambian musician who plays the kora, a guitar-like instrument made from a calabash.

Glass is legendarily prolific, with hundreds of works including 20-plus operas (among them Satyagraha and Akhnaten), the symphonies, sizable batches of string quartets and concerti and solo works for piano and organ. His collaborations include groundbreaking work with Robert Wilson and partnerships with David Bowie, Paul Simon, Yo-Yo Ma and Woody Allen.

His Violin Concerto No. 2 ( The American Four Seasons) is being played in a 30-city tour by Robert McDuffie, who has recorded the piece with the London Philharmonic under Marin Alsop, and he’s just finished a big Partita for solo violin, as well as the Ninth, a three-movement, 50-minute work for a large orchestra.

And in an age when most composers use notation software such as Sibelius or Finale, Glass remains old school.

“I still use pencil and paper. In fact, it’s become a problem. There are no copyists who work with ink anymore. They don’t exist. The reason they don’t is they don’t make the pens anymore. And they don’t make the transparent paper anymore.

“For my manuscript paper, I send away to a very good outfit in Los Angeles who will overnight paper to me’

Even though Glass says his business operation includes a substantial tech component, “I actually think I can write faster with pencil and paper.” A composer friend urged him to try notation software and told him he probably could learn it in three months.

“And I said, ‘David, in three months I can write a string quartet or a symphony.’ I’m not willing to give up a piece of music to write in a different way.”

Still, he acknowledges that “people who work with computers will have access to different technologies and different ways of combining things, and technology will determine content. And I say, ‘God bless ’em.’ Let music change. I’m not trying to hold it back.”

A glance at the March calendar on Glass’ website, lists almost daily performances of his music, from Ireland to Denmark, Mobile to San Antonio, London to Ravenna.

“There’s no question that the music is being played by more people and listened to by more people than before,” he says. “Now, there’s a kind of a lag of, I would say, five to seven or eight years between the public appreciation and the critical appreciation. And, of course, the critics are behind.”

Glass concedes that critics have a tough job trying to assess new music, but he still remembers certain slights.

“I’ve read reviews … where the critic will say, ‘Before the end of the piece, I had to leave the hall, surely to be followed by the rest of the audience.’ And of course, that didn’t happen.”

But he also recalls a piece he read the other day by a critic who had reencountered Glass’ 1991 opera Orphée, part of a trilogy honoring the work of Jean Cocteau.

“It was a very nice review. He said, ‘You know, I liked it so much better this time,’” Glass says. “He put that in the review without explaining why. Well, I knew why. The piece had had time to be in the world, and he was able to bring a different perspective to it than he was able to 20 years ago.

“Probably he also took it a little more seriously because I hadn’t disappeared, the way many people were hoping that I would.”